1. Field of the Invention
The present invention relates to a wavelength division multiplexer (WDM) measurement system for measuring the optical performance characteristics of a WDM, and particularly to an automatic WDM measurement system with high testing speed and automatic data collection and a flexible testing procedure.
2. Description of Related Art
The public""s increasing demand for bandwidth has contributed to an acceleration in the development of WDM technology. Using WDM, data can be transmitted at a high rate on each of several wavelengths of light sharing one optical fiber. To assure that optical characteristics of a WDM meet specifications, WDM testing is necessary.
Present WDM testing usually takes a lot of work and time. For manual testing, the operator has to follow a series of steps, repeatedly tuning laser wavelength settings, and reading power meter data. Furthermore, present WDM testing procedures generally uses a same light path to test Insertion Loss (IL), Polarization Dependent Loss (PDL) and Return Loss (RL), which requires use of an optical coupler to couple part of the optical energy for testing RL. Because an optical coupler has PDL itself, this affects the precision of a test for PDL of a WDM.
It is thus desirable to provide a WDM measurement system which overcomes the above problems.
An object of the present invention is to provide an automatic WDM measurement system which has a high testing speed, automatic data collection, and which allows a flexible testing procedure.
This invention is an automatic WDM measurement system, which combines presently available testing equipment with a PC device and new software, the combination being capable of mostly replacing manual testing with high testing speed, automatic data collection, and a flexible testing procedure.
The WDM measurement system comprises a tunable laser, a power meter module, an RL module, a polarization controller and a PC device. The tunable laser, the power meter module, the RL module and the polarization controller connect with the PC device through a GPIB cable. The PC device has control software for controlling the WDM measurement process.
Light coming from the tunable laser passes through the polarization controller, the polarization state of the light is changed, then the light is transmitted to a port of a WDM. The power meter module connects with output port of the WDM for measuring output light. The RL module is used in measuring return loss of the WDM after measurement of insertion loss and PDL is accomplished. Return loss testing uses a separate light path connecting the WDM with the RL module.
Other objects, advantages, and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.